Finding the Third Proportional to 13,638 and 31,815

Step by Step Solution

1. Step 1: Write the proportion equation
   13,638 : 31,815 = 31,815 : x
2. Step 2: Convert to fraction form
   13,638/31,815 = 31,815/x
3. Step 3: Cross multiply
   13,638x = 31,815 × 31,815
4. Step 4: Simplify right side
   13,638x = 1,012,194,225
5. Step 5: Solve for x
   x = 1,012,194,225/13,638
6. Step 6: Final answer
   x = 74,218.67